WASHINGTON, DC — After having a first MI, men who filled at least one prescription for a drug to treat erectile dysfunction had a 33% lower risk of dying and a 40% lower risk of being hospitalized for heart failure (HF) during a 3-year follow-up compared with other men, in a Swedish registry study[1].

These better outcomes were seen only with phosphodiesterase-5 (PDE-5) inhibitors, not alprostadil, and they appeared to be dose dependent and were significant only in the oldest men, aged 70 to 80.

However, the results "should be interpreted cautiously," Dr Daniel P Andersson (Karolinska Institutet, Stockholm, Sweden) stressed in a press briefing prior to a poster session at the American College of Cardiology (ACC) 2017 Scientific Sessions. The study was also simultaneously published online in Heart.

It was an observational study, so it cannot show cause and effect, and it was not known if the men who received the erectile-dysfunction drugs were less depressed, more physically active, or more happily married.

Thus, the study "is more hypothesis generating rather than a clear statement that all subjects [who have had an MI] should have a PDE-5 inhibitor," Andersson emphasized to heartwire from Medscape.

Physicians should follow ACC/AHA guidelines for prescribing PDE-5 inhibitors (including not to use them with nitrates) and do a patient risk assessment, but this study suggests that if a patient who has had an MI does not have any contraindications, "then you are probably safe to prescribe [a PDE-5 inhibitor], and this person is more likely to survive longer," he said.

Senior author Dr Martin J Holzmann (Karolinska Institutet) agreed but was even more convinced by the strength of the findings.

"It's a huge risk reduction . . . very surprising," and contrary to their original hypothesis, he told heartwire. Moreover, "in clinical epidemiology, if you have a relationship with a 40% risk reduction or a 33% risk reduction, there is no residual confounding that will change that to zero."

"We have patients who have erectile dysfunction, . . . who are diabetic and . . . have had heart disease, and the question is always whether it's safe to put them on a phosphodiesterase inhibitor or not," Dr Amit Tibrewala (Northside Hospital, Atlanta, Georgia), who was not involved in this study, commented to heartwire.

If a patient "can get on the treadmill and function at a reasonable rate, then even post-MI I'm comfortable" prescribing a PDE-5 inhibitor, he continued, but "obviously, we tell them not to use it in conjunction with a nitrate."

This study validates that it's safe to prescribe a PDE-5 inhibitor for certain patients post-MI, "whereas the traditional thinking has been not to use it too much in patients with heart disease," he summarized.

Few Studies of ED Drugs After MI

An estimated 20% to 40% of men aged 60 to 70 have erectile dysfunction, and the risk increases with older age, Andersson noted. However, only a few smaller studies have investigated erectile dysfunction in men with established CVD, including one in men with diabetes, which was previously reported.

They analyzed registry data from 43,145 men aged 18 to 80 who were hospitalized for a first MI during 2007–2013 in Sweden.

The available medications to treat erectile dysfunction at the time were the three oral PDE-5 inhibitors sildenafil (Viagra, Pfizer), tadalafil (Cialis, Lilly/ICOS), and vardenafil (Levitra, Bayer/GlaxoSmithKline) and the injectable prostaglandin alprostadil.

Only 7% of the men filled a prescription for an erectile-dysfunction medication (for a PDE-5 inhibitor in 92% of the cases), which shows there was "definitely undertreatment," Holzmann noted.

At baseline, compared with other men, the men who filled a prescription for an erectile-dysfunction drug were younger (mean age 61 vs 64) and less likely to have diabetes (10% vs 13%), heart failure (0.6% vs 2.1%), previous stroke (3% vs 6%), or active cancer (0.8% vs 1.3%) or be taking nitrates (3.5% vs 5.7%).

Compared with other men, fewer men who received erectile-dysfunction treatment died (3.7% vs 12%) or were hospitalized for HF (1.4% vs 6.0%) during follow-up.

After adjustment for differences in baseline comorbidities and medication use, compared with men who did not fill a prescription for an erectile-dysfunction drug, those who did had a lower risk of all-cause death (HR 0.67, 95% CI 0.55–0.81) and hospitalization for heart failure (HR 0.60, 95% CI 0.44–0.82).

They also had a lower risk for noncardiovascular death or for cardiovascular death, but they had a similar risk for new MI or need for revascularization during follow-up.

The risk of death during follow-up decreased stepwise in men who received one, two to five, or more than five prescriptions for a PDE-5 inhibitor, but this finding is only hypothesis generating, the researchers caution.

Men who were 70 to 80 had a 59% lower risk of death during follow-up if they were taking drugs for erectile dysfunction than if they were not taking these drugs. However, younger men had a similar rate of death whether or not they were taking erectile-dysfunction drugs.

Stage Set for Further Research

"I'm a little worried about the message that goes out that suddenly these medications can be given safely to anybody who has had a prior heart attack," press conference moderator Dr Martha Gulati (University of Arizona , Phoenix) commented.

"You can interpret our results that if you have an active sex life after a heart attack and ask your doctor for a PDE-5 inhibitor, and if you are 70 years old and otherwise healthy" it is probably safe to use a PDE-5 inhibitor, Andersson replied.

The researchers plan to perform a larger study with data for socioeconomic status, marital status, and education.

The study was funded by the Stockholm County Council and the Swedish Heart and Lung Foundation. Holzmann reports receiving consultancy honoraria from Actelion and Pfizer. Andersson has no relevant financial relationships. Gulati discloses receiving a salary from Reata Pharmaceuticals. Tibrewala has no relevant financial relationships.

References

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